Numerous models of heaters for hot air blowers, hot air generators and heaters to heat gases are available according to prior art. However none of these heaters are designed to generate a self-induced divergent flow path to the gas or air after emerging out of the heater.
Reference is made to U.S. Pat. No. 5,303,325, U.S. Pat. No. 5,134,684, U.S. Pat. No. 3,783,236, U.S. Pat. No. 4,987,290, U.S. Pat. No. 5,427,086 and U.S. Pat. No. 4,629,864. Though the prior art devices discloses many designs of air heaters and hot air blowers, none of these devices incorporate any provision to achieve a diverging flow of hot fluid at the outlet of the heater or to alter the hot air flow path after emerging out of the heater without any additional means to create turbulence.
Hence a need is felt to develop a state of the art device for heating air or any other mixture of gaseous fluids individually fed or premixed. The present invention has been developed addressing drawbacks of the prior art devices and the currently available heaters in the market, and also taking into consideration of futuristic requirements. Accordingly, the present invention has been developed to provide an improved and versatile hot air generator that has multiple advantages over the prior art technology available including the disclosure made in patents/patent applications and other published literature. Similar to air, other gaseous fluid also can be heated or mixed or dried.
Summing up, the prior art disclosures suffer from the following often observed limitations
1) None of the above mentioned devices have the capacity to throw air in a radially diverging path.
2) None of the above devices can generate a turbulence that is beneficial in mixing and spreading operations of gases.
3) None of the prior arts can improve the performance of a drying operation in processes like spray drying on their own, and hence the prior art necessitated that the hot air is injected in a tangential manner to create turbulence or obstructions are created in the air path to create turbulence.
4) The prior arts did not provide any means to minimize heating element sag during hot stage resulting in reduced life of the heater. In fact an additional physical structure had to be provided to prevent the heating element sag.
5) In the prior art devices, the length of heating element is limited to overall length of the container in which the heater element is located and its own coil diameter.
To overcome the above deficiencies, an electrically operated hot air generator of improved design which ensures maximum energy efficiency, ensures divergence of hot air at the exit, increased turbulence when allowed to exit into narrow restricted spaces, increased heating element length for longer life, improved element support to minimize element sag during the heating process, simplicity in construction and easiness in control on the heating parameters, and the ability to contribute to the improved performance of different application such as spray drying, shrink wrapping etc.
Increased interest in spray drying of powders and particularly nano-powders by spray Pyrolysis etc., necessitates the development of a proper device to achieve the end results in a more economic and efficient manner. The electrical heater of the present invention offers a simplified solution by which the device can also function as a regular hot air blower to heat spaces and objects where ever required as well as to heat gases and other fluids like steam to increase their temperature.
The heater leaves behind a very small carbon foot print due to its unique design. Further additional accessories to create turbulence can also be avoided. End result is savings in time required for heating, achieving uniformity in heating and mixing, increased energy efficiency, and reduced power requirements.
Therefore the main objective of the present invention is to provide an energy efficient and versatile electrical heater which can be employed in a hot air blower or heat generator.
Yet another object of the present invention is to have a hot air blower with less number of moving parts, compact in size, prolonged heating element life and easiness in assembly and disassembly and reduced operating and maintenance costs.
One more object of the invention is to have a hot air blower which can produce diverging hot air at the exit with uniformity in heat and can also result in proper mixing when more than one fluid is used.
Yet another objective of the present invention is to offer increased support to the heating element to prevent its sagging by inclining the passage or the channel, so that the element can partly rest on the adjoining walls while the element is hot.
Yet another objective is to provide longer channel space within the available body length by inclining the individual passages or the channels preferably of tubular cross section.
Another objective of the present invention is to have a hot air blower which can have universal application
The above mentioned objectives have been achieved by our invention where state of the art technologies are employed in designing and manufacturing the ceramic heater body. Accordingly we have come out with a ceramic heater body with all the passages or channels inclined with reference to the central axis of the heater body, but not parallel to each other, thus allowing the emerging air flow in a divergent manner at the out let with reference to the inlet air entry and away from individual passage/channel outlets causing a diverging hot air stream.